Ask Dave: Can I use Drano in my RV?

Dear Dave, 
Can I use Drano or Liquid-Plumber in my RV plumbing? —Nanci D., Tiffin

From Dave
The answer is no. Here’s why:

This question came up during our weekly RVtravel.com writers’ Zoom meeting. We were discussing Drano (and, similarly, Liquid-Plumr^®) and how new RVers might not know if they can, or can’t, use it in their RV.

Nanci indicated that Tiffin corporate told owners to use Drano for any slow-running sinks and that it was safe to use for pipes and tanks.

Technically the plumbing used in most RVs is very similar to that of residential sinks, as most have gone away from the metal used in the past and now use PVC.

According to the Drano website:

“Drano^® products are powerful enough to dissolve nasty clogs, but they will not harm your plastic or metal pipes, so there’s no need to worry. In fact, Drano Max Gel Clog Remover contains a special ingredient that prevents pipe corrosion.”

It also states that Drano will not affect a septic system or waste system such as that in a campground.

“All Drano products are septic-safe drain cleaners and will not upset the bacterial action in septic systems. Follow the package instructions for the right amount of product to use. Use Drano Max Build-Up Remover on a monthly basis to replenish the bacteria in the septic system that help break down toilet paper and organic matter in pipes.”

So the claim is it will not affect the bacteria in a septic system but that is a different process than the treatment you would typically use for the black water holding tank. According to my contact at Thetford, one of the leading tank treatment developers, they do not recommend any chemical based drain cleaners as studies have shown it affects the efficiency of the break down process. How would you like that job…analyzing sewage breakdown efficiency!

Different types of plastic

Most plumbing fixtures use thick polyvinyl chloride (PVC) piping that is glued together with a primer and PVC cement. This is the strongest connection and holds up longer with road vibration. Since this material is very rigid, exact cuts are required. This is a photo of the Forest River Salem we have been working on with black PVC original plumbing that we are trying to match with a new countertop and sink that are not quite aligned!

Thin-walled polypropylene (PP) is sometimes used for the sink drains which have a “P” trap. These connections are screw-on compression fittings that can be adjusted up or down within the connecting pipe, so they are easier to install. I have found these connections do not hold up when traveling down the road.

I have always reinforced them with silicone tape around the entire connection to keep them fit. You can find a variety of colors here on Amazon.

Also, if a chemical drain cleaner is used in this configuration, the chemical could sit at the lower curve and eat away at the thin plastic. If you have a clog in the “P” trap, it is better to use a snake like this one from Amazon, or just disassemble the “P” trap and remove the clog manually.

Do Not Use Drano!

The debate goes back and forth quite often as the Drano site says it is OK, and I have had owners state that the plastic is the same as a residential plumbing system, which is true. However, a residential plumbing system does not have a holding tank and drain valves that have rubber seals. Valterra, the manufacturer of most of the pull handle drain valves, does not recommend using any chemical-based drain cleaner and has a product that will not deteriorate the seals. It is called Power Max and is available on Amazon here.

Most drain cleaners use sodium hydroxide, or lye, as the main chemical. It creates a chemical reaction that produces heat, which can be caustic to some pipes and especially the rubber seals of the drain valve, as well as the natural lubricant on the spade valve. There is also the potential for deterioration of the monitor panel probes or black water flush valve.

As the chemical sits in the holding tank for a long period of time, it could cause some issues, although I have had many owners state they have used it often with no issues. However, I do not feel comfortable letting harsh chemicals sit for any period time on the rubber seals and gaskets that are so critical for containing the stinky stuff. Plus, most RV plumbing systems are very short runs and can be unclogged easily. Just be sure to use a sink and shower screen so food waste, grease, and hair don’t create the clog in the first place.

 You might also enjoy this from Dave 

Does Dawn dish soap keep RV black tanks clean?

Dear Dave,
I have read that using Dawn dish washing detergent in the RV holding tanks keeps them clean. Is this a good idea?  —John, Renegade Verona LE 2023

Read Dave’s answer.

Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”

Read more from Dave here. 

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